Polyurethane Gel Masses for Pressure Distribution
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Solution Overview
Problem
Existing polyurethane gel masses have limited mechanical property variability, particularly in achieving low hardness with good recovery capacity, and require precise mixing ratios, which restricts their end-use applications.
Innovation Solution
The development of gel masses using NCO prepolymers with a functionality of 2.1 to 5 and polyol components with a mean hydroxyl number of 6 to 112, allowing an isocyanate index range of 15 to 60, enabling homogeneous blending and wide mechanical property variation, especially suitable for pressure-distributing elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polyisocyanate and polyol are mixed in very different amounts to achieve low hardness, then the hardness is reduced, but the mixing precision must be very high to avoid inhomogeneous gel masses
Solution Approach 1:
The invention changes the functional parameters of the reaction components, specifically using polyisocyanates with functionality 2.1-5 and polyols with functionality 3-8 and hydroxyl numbers 6-112, combined with NCO prepolymers having NCO:OH ratios of 2:1 to 8:1. This parameter optimization enables homogeneous mixing at isocyanate indexes of 15-60 while achieving the desired low hardness, resolving the contradiction between hardness reduction and mixing precision requirements
2Adaptability or versatility
If the isocyanate index is increased to vary mechanical properties within wide limits, then the mechanical property adaptability is improved, but the homogeneous blending becomes more difficult
Solution Approach 1:
The invention optimizes multiple parameters simultaneously: polyisocyanate functionality (2.1-5), polyol functionality (3-8), hydroxyl numbers (6-112), NCO:OH ratios in prepolymers (2:1 to 8:1), and isocyanate index (15-60). This coordinated parameter adjustment enables wide mechanical property variability while maintaining homogeneous blending stability
Solution Approach 2:
The invention creates a composite reaction system combining NCO prepolymers with specific polyol components. This composite approach, where the prepolymer serves as a intermediate structure, enables broad mechanical property adjustment through isocyanate index control while ensuring homogeneous mixing through optimized component design
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution allows for the production of gel masses with low hardness and high recovery capacity, suitable for various applications such as cushions and supports, while enabling efficient processing with high-pressure machines, thus expanding their fields of use.
Implementation Method 1
Gel masses are obtained by reacting NCO prepolymers (prepared by reacting a polyisocyanate with a polyoxyalkylenediol monoalkyl ether) and a hydroxyl-containing compound such as, for example, water or a polyol
Data Source
AI summary
The present invention relates to improved gel masses prepared from a reaction mixture of NCO prepolymers and selected compounds containing groups reactive towards isocyanate groups. This invention is also directed to a process for the production of these gel masses and to the production of pressure-distributing elements comprising these gel masses.